CN107955192B - Manufacturing method of tire material - Google Patents

Abstract

The present invention provides a method for producing a tire material that obtains a vulcanized rubber having high fatigue resistance. The method for producing a tire material includes the following steps: step (i): mixing carbon black, a dispersion solvent and a rubber latex solution to produce a carbon black-containing rubber latex solution; step (ii): coagulating the carbon black-containing rubber latex solution, Production of carbon black-containing rubber coagulation; step (iii): adding a compound represented by the general formula (I) to the carbon black-containing rubber coagulation, so that the compound represented by the general formula (I) is added to the carbon-containing carbon black containing water. The black rubber coagulation is dispersed, and at the same time, the rubber coagulation containing carbon black is dehydrated to produce a rubber wet masterbatch; and step (iv): adding silica and silane coupling agent to the rubber wet masterbatch Joint agent, dry mix.

Description

Manufacturing method of tire material

technical field

The present invention relates to a method for producing a tire material, and is a method for producing a tire material using at least carbon black, a dispersion solvent, and a rubber latex solution as raw materials.

Background technique

Conventionally, in the rubber industry, it is known to use a rubber wet-process masterbatch in order to improve processability and dispersibility of carbon black when producing a rubber composition containing carbon black. Specifically, carbon black and a dispersing solvent are mixed in a certain ratio in advance, and a slurry solution containing carbon black obtained by dispersing carbon black in a dispersing solvent by mechanical force and a rubber latex solution are mixed in liquid phase, and then, A coagulant such as an acid is added to make it coagulate, and the coagulation is recovered and dried.

In the case of using a rubber wet masterbatch, compared with the case of using a rubber dry masterbatch obtained by mixing carbon black and rubber in a solid phase, the obtained carbon black has excellent dispersibility, processability, reinforcement, etc. A rubber composition with excellent rubber properties. By using this rubber composition as a raw material, for example, a rubber product such as a pneumatic tire having reduced rolling resistance and excellent fatigue resistance can be produced.

As a rubber composition using a rubber dry masterbatch, rubber compositions containing a specific compound having a nitrogen-containing functional group at the terminal and a carbon-carbon double bond are known (Patent Documents 1 and 2).

Patent Documents 1 and 2 describe that the above-mentioned specific compounds react with functional groups such as carboxyl groups present on the surface of carbon black through the reaction between the terminal functional groups and carbon black, and further, through the carbon-carbon double bond moiety and carbon black. The reaction of polymer radicals and the reaction accompanying vulcanization crosslinking can bond with the polymer. Therefore, it is described that the dispersibility of carbon black in the rubber composition can be improved.

In addition, Patent Documents 1 and 2 describe a method for producing a rubber dry masterbatch: carbon black, rubber, the above-mentioned specific compound, silica, a silane coupling agent, etc. are simultaneously added and mixed in a solid phase ( dry mixing).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2014-95014

Patent Document 2: Japanese Patent Laid-Open No. 2014-95016

SUMMARY OF THE INVENTION

In addition, a rubber product (vulcanized rubber) using a rubber composition as a raw material, particularly a tread rubber for heavy-duty tires, is required to have higher fatigue resistance, but it is obtained from a rubber composition such as the above patent document The vulcanized rubber does not meet this characteristic.

The inventors of the present invention have conducted intensive research, and as a result have found out that the reason is as follows: when the raw rubber of the rubber dry masterbatch, the above-mentioned specific compound, silica and a silane coupling agent are simultaneously added and dry mixed, The viscosity of the kneaded product increases, and the obtained rubber composition contains aggregates of the raw materials, so that the vulcanized rubber cannot exhibit sufficient fatigue resistance.

The present invention has been made in view of the above-mentioned circumstances, and provides a method for producing a tire material that obtains a vulcanized rubber having high fatigue resistance.

The present invention relates to a method for producing a tire material, and is a method for obtaining a tire material using at least carbon black, a dispersion solvent and a rubber latex solution as raw materials, and the method for producing a tire material is characterized by comprising the following steps: step (i) : mixing the carbon black, the dispersing solvent and the rubber latex solution to produce a carbon black-containing rubber latex solution; step (ii): coagulating the obtained carbon black-containing rubber latex solution to produce a carbon black-containing rubber latex solution rubber coagulation; step (iii): adding a compound represented by the general formula (I) to the obtained carbon black-containing rubber coagulation, so that the compound represented by the general formula (I) is added to the Disperse in the rubber coagulation of carbon black, at the same time, dehydrate the rubber coagulum containing carbon black to manufacture a rubber wet masterbatch; and step (iv): adding two Silica and silane coupling agent are dry mixed.

[Chemical formula 1]

(In formula (I), R ¹ and R ² represent a hydrogen atom and an alkyl, alkenyl or alkynyl group having 1 to 20 carbon atoms, and R ¹ and R ² may be the same or different. M ⁺ represents a sodium ion, Potassium ion or Lithium ion.)

In the production method, in the step (iii), the compound represented by the general formula (I) described above is dispersed in the carbon black-containing rubber coagulation material containing moisture, and simultaneously, the carbon black-containing rubber coagulation material is subjected to Dehydration. Generally, rubber for tires exhibits hydrophobicity in a dry state. On the other hand, the compound represented by the general formula (I) exhibits hydrophilicity, so even if the rubber in a dry state and the compound represented by the general formula (I) are dry-mixed, the compound represented by the general formula (I) It is also difficult to improve the dispersibility of the represented compound. However, in the above-mentioned production method, in the step (iii) corresponding to the dehydration step, the compound represented by the general formula (I) is dispersed in the carbon black-containing rubber coagulated substance containing moisture, so it is presumed that the general formula The dispersibility of the compound represented by (I) is remarkably enhanced by moisture. As a result, the compound represented by the general formula (I) can be dispersed at a high level in the rubber coagulate containing carbon black.

Once the compound represented by the general formula (I) is dispersed in the carbon black-containing rubber coagulation, even if the carbon black-containing rubber coagulation is dehydrated, the dispersibility of the compound represented by the general formula (I) is maintained, so , the dispersibility of the compound represented by the general formula (I) is remarkably improved even in the final dried rubber wet masterbatch or tire material. Therefore, since the dispersibility of the carbon black contained in the vulcanized rubber is also improved, the vulcanized rubber obtained from the tire material by the above-described production method is superior in fatigue resistance as compared with the vulcanized rubber using the dry rubber masterbatch.

Moreover, in the said manufacturing method, in a process (iv), a silica and a silane coupling agent are added to the rubber wet masterbatch obtained in a process (iii), and dry mixing is performed. It is presumed that the carbon black contained in the rubber wet masterbatch has high dispersibility in the rubber and is covered with the compound represented by the general formula (I). Therefore, even in the step (iv), in the rubber wet masterbatch Adding silica and a silane coupling agent to the mixture does not easily increase the viscosity of the kneaded product.

Detailed ways

The method for producing a tire material according to the present invention uses at least carbon black, a dispersion solvent, and a rubber latex solution as raw materials.

As the carbon black, for example, conductive carbon blacks such as acetylene black and Ketjen black can be used in addition to carbon blacks commonly used in the rubber industry such as SAF, ISAF, HAF, FEF, and GPF. The carbon black may be a granulated carbon black obtained by granulating in consideration of its workability in the general rubber industry, or may be an ungranulated carbon black. Carbon black may be used alone or in combination of two or more.

For the carbon black, the nitrogen adsorption specific surface area is preferably 15 to 150 m ² /g from the viewpoint of excellent heat release properties and viscosity retention performance of the vulcanized rubber. In particular, carbon black having a nitrogen adsorption specific surface area of 80 to 150 m ² /g is preferable as a raw material for a tread rubber for heavy duty tires. In addition, the content of the carbon black is preferably 30 to 80 parts by weight, more preferably 40 to 70 parts by weight, with respect to 100 parts by weight of the rubber component contained in the tire material.

As the dispersing solvent, water is particularly preferably used, but, for example, water containing an organic solvent may be used. The dispersing solvent may be used alone or in combination of two or more.

As the rubber latex solution, a natural rubber latex solution and a synthetic rubber latex solution can be used.

The natural rubber latex solution is a natural product obtained through plant metabolism, and a natural rubber/water-based natural rubber latex solution in which the dispersing solvent is water is particularly preferred. The number average molecular weight of the natural rubber in the natural rubber latex is preferably 2 million or more, and more preferably 2.5 million or more. As for the natural rubber latex solution, concentrated latex, fresh latex called field latex, and the like can be used without distinction. As a synthetic rubber latex solution, the synthetic rubber latex solution obtained by producing a styrene-butadiene rubber, a butadiene rubber, a nitrile rubber, and a chloroprene rubber by emulsion polymerization is mentioned, for example. The rubber latex solution may be used alone or in combination of two or more.

In the present invention, when dehydrating the carbon black-containing rubber coagulate obtained from at least carbon black, a dispersing solvent and a rubber latex solution as raw materials, the carbon black-containing rubber coagulate is added by the general formula ( I) Compounds represented by:

[Chemical formula 2]

(In formula (I), R ¹ and R ² represent a hydrogen atom and an alkyl, alkenyl or alkynyl group having 1 to 20 carbon atoms, and R ¹ and R ² may be the same or different. M ⁺ represents a sodium ion, Potassium ion or Lithium ion.).

In particular, from the viewpoint of improving the affinity for carbon black, it is preferable to use a compound represented by the general formula (I') in which R ¹ and R ² in the general formula (I) are hydrogen atoms and M ⁺ is a sodium ion. Compound:

[Chemical formula 3]

Hereinafter, the manufacturing method of the tire material which concerns on this invention is demonstrated concretely. This production method is a method for producing a tire material by using at least carbon black, a dispersion solvent and a rubber latex solution as raw materials to obtain a tire material, and the method for producing a tire material is characterized by comprising the following steps: step (i): The carbon black, the dispersing solvent and the rubber latex solution are mixed to produce a carbon black-containing rubber latex solution; step (ii): coagulating the obtained carbon black-containing rubber latex solution to produce a carbon black-containing rubber coagulation solution Step (iii): adding the compound represented by the general formula (I) to the obtained carbon black-containing rubber coagulation, so that the compound represented by the general formula (I) is added to the Disperse in the rubber coagulation of carbon black, at the same time, dehydrate the rubber coagulum containing carbon black to manufacture a rubber wet masterbatch; and step (iv): adding two Silica and silane coupling agent are dry mixed.

<(1) Step (i)>

In the step (i) of the present invention, carbon black, a dispersion solvent, and a rubber latex solution are mixed to produce a carbon black-containing rubber latex solution. In particular, in the present invention, the step (i) preferably includes the step of: step (i-(a)): when dispersing the carbon black in the dispersing solvent, adding in the rubber latex solution At least a part, thereby producing a slurry solution containing the carbon black with attached rubber latex particles; and step (i-(b)): mixing the slurry solution containing the carbon black with attached rubber latex particles and The remaining rubber latex solutions are mixed to prepare a rubber latex solution containing the carbon black to which rubber latex particles have adhered. Hereinafter, the step (i-(a)) and the step (i-(b)) will be described.

<Process (i-(a))>

In the step (i-(a)) of the present invention, when dispersing the carbon black in the dispersing solvent, at least a part of the rubber latex solution is added, thereby producing a slurry solution containing the carbon black to which the rubber latex particles adhered . The rubber latex solution may be mixed with a dispersing solvent in advance, and then carbon black may be added to disperse it. Alternatively, carbon black may be added to the dispersing solvent, and then the rubber latex solution may be added at a predetermined addition rate to disperse the carbon black in the dispersing solvent, or carbon black may be added to the dispersing solvent, and then, A certain amount of the rubber latex solution is added in several times while the carbon black is dispersed in the dispersing solvent. By dispersing carbon black in a dispersion solvent in a state where the rubber latex solution exists, a slurry solution containing carbon black to which rubber latex particles adhere can be produced. As the addition amount of the rubber latex solution in the step (i-(a)), the total amount added in the step (i-(a)) and the step (i-(b)) is based on the total amount of the rubber latex solution used. amount) is 0.075 to 12% by weight.

In the step (i-(a)), the amount of the rubber solid content of the rubber latex solution to be added is preferably 0.25 to 15%, more preferably 0.5 to 6% by weight to carbon black. In addition, the concentration of the rubber solid content in the added rubber latex solution is preferably 0.2 to 5% by weight, and more preferably 0.25 to 1.5% by weight. In these cases, it is possible to produce a wet rubber masterbatch in which rubber latex particles are reliably adhered to carbon black and the degree of dispersion of carbon black is improved.

In the step (i-(a)), as a method of mixing carbon black and a dispersing solvent in the presence of a rubber latex solution, for example, the use of a high shear mixer, a High Shear Mixer, a homogenizer, and a ball mill can be mentioned. , bead mill, high pressure homogenizer, ultrasonic homogenizer, colloid mill and other common dispersing machines to disperse carbon black.

The "high-shear mixer" is a mixer including a rotor and a stator, and refers to a state where a precise gap is provided between the rotor that can rotate at high speed and the fixed stator, and the rotor is rotated to generate high-shear. Mixer for cutting action. Preferably, the gap between the rotor and the stator is set to 0.8 mm or less, and the peripheral speed of the rotor is set to be 5 m/s or more in order to generate the high shearing action. As this high shear mixer, a commercial item can be used, for example, "High Shear Mixer" manufactured by SILVERSON can be mentioned.

In the present invention, when carbon black and a dispersing solvent are mixed in the presence of a rubber latex solution to produce a slurry solution containing carbon black to which rubber latex particles adhere, a surfactant may be added to improve the dispersibility of carbon black. As the surfactant, known surfactants in the rubber industry can be used, and examples thereof include nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants. In addition, alcohols, such as ethanol, may be used instead of a surfactant, or alcohols, such as ethanol, may be used in addition to a surfactant. However, when a surfactant is used, there is a concern that the rubber properties of the final vulcanized rubber will decrease. Therefore, the compounding amount of the surfactant is preferably 2 parts by weight relative to 100 parts by weight of the rubber solid content of the rubber latex solution. Below, it is more preferable that it is 1 weight part or less, and it is preferable that a surfactant is not used substantially.

<Process (i-(b))>

In the step (i-(b)) of the present invention, the slurry solution and the remaining rubber latex solution are mixed to produce a rubber latex solution containing carbon black to which rubber latex particles have adhered. The method of mixing the slurry solution and the remaining rubber latex solution in a liquid phase is not particularly limited, and for example, a high shear mixer, a high shear mixer, a homogenizer, a ball mill, a bead mill, and a high pressure homogenizer can be used. , ultrasonic homogenizer, colloid mill and other ordinary dispersing machines to mix the slurry solution and the remaining rubber latex solution. If necessary, the entire mixing system such as a disperser may be heated during mixing.

With regard to the remaining rubber latex solution, in consideration of the dehydration time and labor in the subsequent step (iii), the concentration of the rubber solid content is preferably higher than that of the rubber latex solution added in the step (i-(a)). The concentration, specifically, the concentration of the rubber solid content is preferably 10 to 60% by weight, and more preferably 20 to 30% by weight.

<(2) Step (ii)>

In the step (ii) of the present invention, a carbon black-containing rubber latex solution is coagulated to produce a carbon black-containing rubber coagulation product. As a coagulation method, the method of containing a coagulant in the rubber latex solution containing carbon black to which rubber latex particles adhered is mentioned. In this case, as the coagulant, salts such as acids such as formic acid and sulfuric acid, and salts such as sodium chloride, which are generally used for coagulation of rubber latex solutions, can be used. It should be noted that, after the step (ii) and before the step (iii), a solid-liquid separation step such as a centrifugal separation step and a heating step may be provided as necessary for the purpose of appropriately reducing the amount of water contained in the carbon black-containing rubber coagulum. .

<(3) Step (iii)>

In the step (iii) of the present invention, a rubber wet-process masterbatch is produced by dehydrating the carbon black-containing rubber coagulum. In the step (iii), for example, a uniaxial extruder can be used to dehydrate the carbon black-containing rubber coagulated product while applying shear force to it while heating to 100 to 250°C. In the present invention, particularly in the step (iii), the compound represented by the general formula (I) is added to the carbon black-containing rubber coagulate, and the compound represented by the general formula (I) is added to the carbon-containing carbon black containing water. The black rubber coagulum is dispersed, and at the same time, the carbon black-containing rubber coagulum is dehydrated. The moisture content of the carbon black-containing rubber coagulum before the start of the step (iii) is not particularly limited, but it is preferable to provide the solid-liquid separation step or the like as necessary to adjust the Wa/Wb described later in an appropriate range. Moisture rate.

As described above, the compound represented by the general formula (I) is dispersed in the carbon black-containing rubber coagulate in the presence of moisture, whereby its dispersibility is remarkably improved. In particular, when the compound represented by the general formula (I) is added, the water content (Wa) of the rubber coagulated product containing carbon black is preferably 1 part by weight, for example, with respect to 100 parts by weight of the rubber component in the rubber coagulated product Above, more preferably 10 parts by weight or more, and preferably 800 parts by weight or less, more preferably 600 parts by weight or less. In addition, when adding the compound represented by the general formula (I), the content (Wb) of the compound represented by the general formula (I) is preferably, for example, 0.1 weight part with respect to 100 parts by weight of the rubber component in the rubber coagulate. part or more, more preferably 0.5 parts by weight or more, and preferably 10 parts by weight or less, more preferably 5 parts by weight or less. Further, the ratio of Wa to Wb (Wa/Wb) is preferably 1≦Wa/Wb≦8100. If Wa/Wb is less than 1, the dispersibility of the compound represented by the general formula (I) in the carbon black-containing rubber coagulate may not be sufficiently improved. In order to further improve the dispersibility of the compound represented by the general formula (I), Wa/Wb is preferably 1 or more. On the other hand, when Wa/Wb exceeds 8100, since the water to be removed remarkably increases, the productivity of the rubber wet masterbatch tends to deteriorate. In consideration of productivity of the rubber wet masterbatch, Wa/Wb is preferably 7400 or less.

After the step (iii), a drying step may be additionally provided as required, so as to further reduce the moisture content of the rubber wet masterbatch. As a drying method of a rubber wet masterbatch, various drying apparatuses, such as a uniaxial extruder, an oven, a vacuum dryer, and an air dryer, can be used, for example.

<(4) Step (iv)>

In the step (iv) of the present invention, a tire material is produced by adding silica and a silane coupling agent to the wet rubber masterbatch, and performing dry mixing.

The silica is not limited as long as it can be used as a reinforcing filler, but wet silica (hydrous silicic acid) is preferred. The colloidal properties of silica are also not particularly limited, but the nitrogen adsorption specific surface area (BET) obtained by the BET method is preferably 150 to 250 m ² /g, and more preferably 180 to 230 m ² /g. In addition, the BET of silica can be measured according to the BET method described in ISO 5794. Silica may be used alone or in combination of two or more.

The content of the silica is preferably 0.5 to 40 parts by weight with respect to 100 parts by weight of the rubber component contained in the tire material. From the viewpoint of improving the fatigue resistance of the vulcanized rubber, the content of silica is preferably 1 part by weight or more, more preferably 1.5 parts by weight or more, based on 100 parts by weight of the rubber component contained in the tire material. In addition, from the viewpoint of suppressing an increase in the viscosity of the tire material, the content of silica is preferably 35 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the rubber component contained in the tire material.

As the silane coupling agent, any silane coupling agent generally used for rubber may be used, and examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)tetrasulfide, Ethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) tetrasulfide, bis(4-triethoxysilylbutyl) disulfide, bis(2-triethoxysilylethyl) disulfide Sulfide silanes such as (3-trimethoxysilylpropyl)tetrasulfide and bis(2-trimethoxysilylethyl)disulfide; 3-mercaptopropyltrimethoxysilane, 3-mercapto Mercaptosilanes such as propyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyldimethylmethoxysilane, and mercaptoethyltriethoxysilane; 3-octanoyl Thio-1-propyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane and other protected mercaptosilanes, etc. The silane coupling agent may be used alone or in combination of two or more.

The content of the silane coupling agent is preferably 2% by weight or more, more preferably 4% by weight or more, and preferably 20% by weight or less, based on the weight of the silica, from the viewpoint of sufficiently exerting the effect of addition. More preferably, it is 15 weight% or less.

From the viewpoint of suppressing the increase in the viscosity of the tire material and improving the fatigue resistance of the vulcanized rubber, the step (iv) may include the following steps: step (iv-(a)): adding the The carbon black and the compound represented by the general formula (I) are dry-mixed to produce a kneaded product; and step (iv-(b)): adding silica and a silane coupling agent to the obtained kneaded product Joint agent, dry mix. By adopting this process, the bond produced by carbon black and the compound represented by the general formula (I) and the bond produced by silica and the silane coupling agent can be mixed in separate steps, so it is not easy to Poor mixing due to a sudden increase in viscosity occurs, and the increase in viscosity of the kneaded product can be suppressed.

In the step (iv), various compounding agents can also be used. Examples of compounding agents that can be used include sulfur-based vulcanizing agents, vulcanization accelerators, antiaging agents, zinc oxide, methylene acceptors and methylene donors, stearic acid, vulcanization accelerators, and vulcanization retarders. Compounding agents commonly used in the rubber industry, such as softeners, organic peroxides, waxes and oils, and processing aids.

The sulfur used as the sulfur-based vulcanizing agent may be ordinary sulfur for rubber, and for example, powder sulfur, precipitated sulfur, insoluble sulfur, highly dispersible sulfur, and the like can be used. The sulfur-based vulcanizing agent may be used alone or in combination of two or more.

The content of the sulfur is preferably 0.3 to 6.5 parts by weight with respect to 100 parts by weight of the rubber component contained in the tire material. If the sulfur content is less than 0.3 parts by weight, the crosslinking density of the vulcanized rubber is insufficient, resulting in a decrease in rubber strength, etc.; if the sulfur content exceeds 6.5 parts by weight, especially heat resistance and durability are deteriorated. In order to ensure good rubber strength of the vulcanized rubber and further improve heat resistance and durability, the content of sulfur is more preferably 1.0 to 5.5 parts by weight relative to 100 parts by weight of the rubber component contained in the tire material.

Examples of the vulcanization accelerator include sulfenamide-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiourea-based vulcanization accelerators, and guanidine-based vulcanization accelerators, which are commonly used in rubber vulcanization. vulcanization accelerators such as vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, etc. The vulcanization accelerator may be used alone or in combination of two or more.

The content of the vulcanization accelerator is preferably 1 to 5 parts by weight with respect to 100 parts by weight of the rubber component contained in the tire material.

Examples of the antiaging agent include aromatic amine antiaging agents, amine-ketone antiaging agents, monophenol antiaging agents, bisphenol antiaging agents, and polyphenol antiaging agents, which are generally used in rubber. Antiaging agents such as aging agents, dithiocarbamate antiaging agents, and thiourea antiaging agents. Antiaging agents may be used alone or in combination of two or more.

The content of the anti-aging agent is preferably 1 to 5 parts by weight with respect to 100 parts by weight of the rubber component contained in the tire material.

In addition, in the step (iv), in order to adjust the content of the rubber component contained in the tire material, rubber may be used. As the rubber, diene-based rubbers known to those skilled in the art, such as natural rubber (NR), polyisoprene rubber (IR), polystyrene butadiene rubber (SBR), polybutadiene rubber ( BR), chloroprene rubber (CR), nitrile rubber (NBR), etc.

In the step (iv), the mixing method of each raw material (each component) is not particularly limited. For example, components other than the vulcanization components such as a sulfur-based vulcanizing agent and a vulcanization accelerator are added and kneaded in an arbitrary order. method of simultaneously adding and kneading components other than vulcanization-based components such as a sulfur-based vulcanizing agent and a vulcanization accelerator, and a method of simultaneously adding and kneading all components, etc. However, from the viewpoint of preventing an increase in the viscosity of the kneaded product, it is preferable to mix carbon black and the compound represented by the general formula (I) with silica and a silane coupling agent as in the steps (iv-(a)) and It mixes in a different kneading process (step) like process (iv-(b)).

As the dry mixing, for example, a method of kneading using a kneader commonly used in the rubber industry, such as a Banbury mixer, a kneader, and a roll, is exemplified. The number of times of kneading may be one or more times. The kneading time varies depending on the size of the kneader to be used, etc., but it is usually only about 2 to 5 minutes. In addition, when the tire material does not contain the vulcanized component, the discharge temperature of the kneader is preferably 120 to 170°C, and more preferably 120 to 150°C. When the tire material contains the vulcanized component, the discharge temperature of the kneader is preferably 80 to 110°C, and more preferably 80 to 100°C.

In the present invention, the compound represented by the general formula (I) and water (with respect to 100 parts by weight of the rubber component) may be added to the mixture of carbon black and rubber in place of the steps (i) to (iii). about 1 to 10 parts by weight) to obtain a rubber masterbatch in which the compound represented by the general formula (I) is dispersed, and then, in the step (iv), in place of the rubber wet masterbatch, the above-mentioned From the obtained rubber masterbatch, a tire material was produced. By this production method, the dispersibility of the compound represented by the general formula (I) in the rubber masterbatch produced in the intermediate stage of the production of the tire material can be improved, and therefore, the compound represented by the general formula (I) in the rubber masterbatch The dispersibility in the tire material obtained by rubber mixing is excellent.

As the carbon black, the same carbon black as that used in the production method of the rubber wet masterbatch can be used. The rubber can be a diene-based rubber known to those skilled in the art, such as natural rubber (NR), polyisoprene rubber (IR), polystyrene butadiene rubber (SBR), polybutadiene rubber ( BR), chloroprene rubber (CR), nitrile rubber (NBR), etc.

Since the vulcanized rubber obtained from the tire material of the present invention has high fatigue resistance, it is suitable for a tread rubber for heavy duty tires.

Example

The present invention will be described below with reference to Examples, but the present invention is not limited by these Examples.

(using raw materials)

a) Carbon Black:

Carbon black "N234" (nitrogen adsorption specific surface area: 126 m ² /g), "SEAST 7HM" (manufactured by Tokai Carbon Co., Ltd.)

b) Dispersing solvent: water

c) Rubber latex solution:

Natural rubber latex solution "NR field latex" (manufactured by Golden Hope) (DRC=31.2%)

d) Compounds represented by the general formula (I):

(2Z)-4-[(4-aminophenyl)amino]-4-oxo-2-butenoate sodium (manufactured by Sumitomo Chemical Co., Ltd.)

e) Coagulant: Formic acid (1st grade 85%, diluted to 10% solution and adjusted to pH 1.2), (manufactured by NacalaiTesque)

f) Silica: "Nipsil AQ" (BET=205 m ² /g) (manufactured by Nippon Silica Industries Co., Ltd.)

g) Silane coupling agent: bis(3-triethoxysilylpropyl) disulfide, "Si75" (manufactured by Degussa Corporation)

h) Zinc oxide: "Zinc Hua No. 3" (manufactured by Mitsui Metals Co., Ltd.)

i) Stearic acid: "LUNAC S-20" (manufactured by Kao Corporation)

j) Sulfur: "5% oil-extended fine powder sulfur" (manufactured by Tsurumi Chemical Industry Co., Ltd.)

k) Vulcanization accelerator:

(A): N-cyclohexyl-2-benzothiazole sulfenamide "SANCELER CM" (manufactured by Sanshin Chemical Industry Co., Ltd.)

(B): 1,3-Diphenylguanidine "Nocceler D" (manufactured by Ouchi Shinshin Chemical Co., Ltd.)

l) Natural Rubber (NR): "RSS#3"

m) Polybutadiene: "BR150B" (manufactured by Ube Industries, Ltd.)

<Example 1>

To the natural rubber thin latex aqueous solution whose concentration was adjusted to 0.52 wt %, carbon black was added in the compounding amount described in Table 1 (the concentration of carbon black with respect to water was 5 wt %), and the carbon black was dispersed in ROBOMIX manufactured by PRIMIX Corporation. However (conditions of this ROBOMIX: 9000 rpm, 30 minutes), the slurry solution containing the carbon black with which the natural rubber latex particle|grains adhered as described in Table 1 was produced (step (i)-(a)). Next, the natural rubber latex solution (28% by weight) was added to the slurry solution containing the carbon black to which the natural rubber latex particles adhered produced in the step (i-(a)) in the amount described in Table 1, Next, the mixture was mixed using a SM-L56 household mixer manufactured by SANYO (mixer conditions: 11,300 rpm, 30 minutes) to produce a rubber latex solution containing carbon black to which natural rubber latex particles adhered (step (i)).

To the natural rubber latex solution containing the carbon black to which the natural rubber latex particles adhered produced in the step (i), formic acid was added as a coagulant until the pH of the whole solution became 4 to produce a natural rubber coagulate product containing carbon black ( Process (ii)). If necessary, a solid-liquid separation step is performed on the obtained carbon black-containing natural rubber coagulate, and the carbon black-containing natural rubber coagulate and the compound represented by the general formula (I) adjusted to the water content described in Table 1 are charged In a V-01 screw press manufactured by Suehiro EPM, the compound represented by the general formula (I) is dispersed in the natural rubber coagulation material containing carbon black, and at the same time, the natural rubber coagulation material containing carbon black is dehydrated to produce Rubber wet masterbatch (step (iii)). Table 1 shows the values of Wa/Wb in the step (iii).

Tires were produced by dry mixing the wet rubber masterbatch obtained above and each raw material described in Table 1 using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150°C). Materials (Non-Process Kneading Step 1 of Step (iv)). Sulfur, vulcanization accelerator (A), and vulcanization accelerator (B) described in Table 1 were added to the obtained tire material, and were dry-blended using a Banbury mixer (kneading time: 1 minute, discharge temperature : 90° C.), thereby producing an unvulcanized tire material (processing and kneading step of step (iv)). In addition, the compounding ratio in Table 1 is represented by the weight part (phr) when the total amount of the rubber component contained in a tire material is 100 weight part.

<Examples 2 to 4>

An unvulcanized tire material was produced by the same method as in Example 1, except that the compounding amounts of the silica and the silane coupling agent were changed as described in Table 1.

<Examples 5 and 6>

In the steps (i) to (iii) in Example 1, except that the compounding amounts of carbon black, the compound represented by the general formula (I), and water were changed as shown in Table 1, the same procedures as in Example 1 were used. The same method is used to make rubber wet masterbatch. A kneaded product was produced by dry mixing the obtained rubber wet masterbatch and each raw material described in Table 1 using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150°C). (Non-processing kneading step 1 of step (iv)). The silica and the silane coupling agent described in Table 1 were added to the obtained kneaded product, and dry mixing was performed using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150°C), thereby , to manufacture tire material (non-processing kneading step 2 of step (iv)). Further, sulfur, vulcanization accelerator (A), and vulcanization accelerator (B) described in Table 1 were added to the obtained tire material, and were dry-blended using a Banbury mixer (kneading time: 1 minute, Discharge temperature: 90° C.), thereby producing an unvulcanized tire material (processing and kneading step of step (iv)).

<Comparative Examples 1 to 2>

Each raw material described in Table 2 was dry-mixed using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150° C.) to manufacture tire materials (non-process kneading step 1 of step (iv)) . Next, the sulfur, vulcanization accelerator (A), and vulcanization accelerator (B) described in Table 2 were added to the obtained tire material, and were dry-blended using a Banbury mixer (kneading time: 1 minute). , discharge temperature: 90° C.), thereby producing an unvulcanized tire material (processing and kneading step of step (iv)).

<Comparative Example 3>

Each raw material described in Table 2 was dry-mixed using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150°C) to produce a kneaded product (non-processing kneading step 1 of step (iv)) ). The silica and silane coupling agent described in Table 2 were added to the obtained kneaded product, and dry mixing was carried out using a Banbury mixer (kneading time: 3 minutes, discharge temperature: 150°C), thereby , to manufacture tire material (non-processing kneading step 2 of step (iv)). Further, sulfur, vulcanization accelerator (A), and vulcanization accelerator (B) described in Table 2 were added to the obtained tire material, and dry mixing was performed using a Banbury mixer (kneading time: 1 minute, discharge temperature: 90° C.), thereby producing an unvulcanized tire material (processing and kneading step of step (iv)).

<Comparative Example 4>

In the step (iii) of Example 1, except that the compound represented by the general formula (I) was not added to produce a rubber wet-process masterbatch, the raw materials described in Table 2 were used, and the same procedures as in Example 1 were used. method to manufacture unvulcanized tire material.

<Comparative Example 5>

Before the step (iii) of Example 1, the carbon black-containing natural rubber coagulation product was dried until the moisture content was 0%, and the carbon black-containing natural rubber coagulation product in a dry state that did not contain moisture was used, except that , using each raw material described in Table 2, by the same method as Example 1, an unvulcanized tire material was produced.

The following viscosity evaluations were performed on the unvulcanized tire materials obtained in the above-mentioned Examples and Comparative Examples. In addition, vulcanized rubber was produced by vulcanizing the unvulcanized tire materials obtained in the above-mentioned Examples and Comparative Examples under the conditions of 150° C. and 30 minutes. The following fatigue resistance evaluation was performed with respect to the obtained vulcanized rubber. The evaluation results are shown in Tables 1 and 2.

<Evaluation of viscosity>

For the evaluation of viscosity, based on JIS K6300, a non-rotor Mooney tester manufactured by Toyo Seiki Co., Ltd. was used to preheat the unvulcanized tire material at 100° C. for 1 minute, and then the torque after 4 minutes was measured in Mooney units. The value of Examples 1 to 5 and Comparative Examples 3 to 5 is represented by an index obtained from the value of Comparative Example 1 as 100. In addition, Example 6 is represented by the index obtained by the value of the comparative example 2 being 100. The smaller the index, the lower the viscosity (Mooney viscosity) and the better the processability.

<Evaluation of fatigue resistance>

The evaluation of fatigue resistance was carried out at a temperature of 23°C based on the evaluation of flexural fatigue resistance according to JIS K6260 (Demesian flexural crack test), and the crack growth of the test piece of the vulcanized rubber was obtained to 2mm times. Examples 1 to 5 and Comparative Examples 3 to 5 are represented by indices obtained by the value of Comparative Example 1 being 100. Example 6 is represented by an index obtained from the value of Comparative Example 2 as 100. The smaller the numerical value, the better the fatigue resistance.

Table 1

Table 2

Claims (3)

1. a method for manufacturing a tire material, which is a method for obtaining a tire material with at least carbon black, a dispersion solvent and a rubber latex solution as raw materials, The manufacturing method of the tire material is characterized by comprising the following steps: Step (i): mixing the carbon black, the dispersion solvent and the rubber latex solution to produce a carbon black-containing rubber latex solution; Step (ii): coagulating the obtained carbon black-containing rubber latex solution to produce a carbon black-containing rubber coagulum; Step (iii): adding a compound represented by the general formula (I) to the obtained carbon black-containing rubber coagulate, and making the compound represented by the general formula (I) in the carbon black-containing rubber containing moisture dispersing in the coagulum, and at the same time, dewatering the carbon black-containing rubber coagulum to produce a rubber wet masterbatch; and Step (iv): adding silica and a silane coupling agent to the obtained rubber wet masterbatch, and performing dry mixing, [Chemical formula 1]

In formula (I), R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group or an alkynyl group having 2 to 20 carbon atoms, and R ¹ and R ² may be the same or different, M ⁺ represents sodium ion, potassium ion or lithium ion. 2. The method for producing a tire material according to claim 1, wherein In the step (iii), when the compound represented by the general formula (I) is added, the water content in the carbon black-containing rubber coagulate is Wa, and the compound represented by the general formula (I) When the content of Wb is Wb, 1≤Wa/Wb≤8100 is satisfied. 3. The method for producing a tire material according to claim 1 or 2, wherein The silica is 0.5 to 40 parts by weight with respect to 100 parts by weight of the rubber component contained in the tire material.